Unit tests using `r` as a variable name are shaddowed by PDB commands

[julianstirling]

Describe the bug
Most code that uses TestClient gets a response from the server as r = client.get(...) [or similar for post requests. However, if we use pytests --pdb flag to drop into the terminal, it is impossible to read this value as r is one of the many single letter PDB commands.

It can be reassigned, but by this time you have accidentally returned as this is what r means in PDB

This is an easy fix, and will improve variable naming and test readability at the same time.

To Reproduce
Make a TestClient unit test fail with the --pdb flag. Try to read r by typing r. You will be returned out of PDB

Expected behaviour
The response should print.

System:

• OS: Kubuntu 24.04
• Python version: 3.11
• Version: 0.0.12

Additional context
Add any other context about the problem here.

[rwb27]

I guess pp r would work - but as you say r is a bit of a lazy variable name anyway.

If we do go through all the test client code it is worth us deciding when we should be using http requests directly, when it's sensible to use the temp_client module in the tests folder (possibly never), and when it's better to use a ThingClient. Currently the test code is quite inconsistent in that regard.